What a major PITA this has been. But I was finally able to work this out by finding the right setting in the Page Set Up options in MS-Word.. Go to page layout. Select Size Choose More Paper Sizes (It’s a the bottom of the popup menu.) The next menu is not one I had ever noticed or seen before. Here you can select the tray your Index cards or envelopes are in, i.e. Cassette 1 I tried to paste the image of the menu so you could visualize it here. Alas I couldn’t.